Balanced hydraulic pump or motor



May 15, 1923. 1,455,443

I w. F. MAYER BALANCED HYDRAULIC PUMP OR MOTOR Filed Nov. 12, 1919 2 Sheets-Sheet 1 INVENTOR. WM 64% .4 TTORNE Y.

. W. F. MAYER BALANCED HYDRAULIC PUMP OR MOTOR 2 SheetS-Sheet 2 Filed Nov. 12 1919 k INVEN/TOR. W W ,M BY

A TTORNE Y.

Patented May 15', 1923.

UNITED STATES PATENT OFFICE.

WALDEMAR F. MAYER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO TAYLOR- WHARTON IRON AND STEEL COMPANY, OF HIGH BRIDQE, NEW JERSEY, A CORPO- RATION OF'NEW JERSEY.

BALANCED HYDRAULIC PUMP OR MOTOR. I

Application filed November To all'whom it my concern:

Be it known that I, VVALDEMAR F. MAYER, a citizen of Switzerland, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Balanced Hydraulic Pumps or Motors,of which the following is a specification.

-This invention relates to an improvement in hydraulic transmissions, wherein the valve is balanced against the working fluid pressures.

The invention is illustrated in the accompanying drawings, in which Fig. 1 is a view in elevation, partly in section of the improved transmission.

Fig. 2 is a section of the motor forming part of such transmission.

Fig. 3 is a development of the valve for such motor.

Figs. 4 to 11 are diagrammatic views illustrating the principle of the balanced motor.

In the drawings, with particular refer-' ence to Fig. 1, there is shown a complete transmission comprising a prime mover 1, arranged to drive a variable-stroke balanced pump 2, through a coupling 3. A hydraulic motor, indicated generally at 5, forms part of the transmission, and comprises a crankframe 6, secured to a foundation 7, here shown as a reservoir 8. The cylinder body 9 and housing 10 of the motor are secured to and supported by the crank-frame, and the pump 2 is secured toand supported from the motor 5.

The cylinders 11 of the motor have ports 12, and pistons or plungers 13 are operative in suchcylinders. The connecting rods 14 of the plungers are connected to cranks 15, mounted in bearings 16 in the crank frame. The shafts 17 of the cranks 15, extend beyond the crank frame, and are provided with pinions 18, arranged in mesh with a ear, here shown as an annular gear 19.

he gear 19 is rotatively mounted on a spindle 20, secured in the crank frame.

The control valve 21, mounted for rotation on the pump shaft, is shown as divided into. four equal parts, that is four circumferentially alined passages, as 22, 23, 24, and 25 adapted to successively register with the cylinder ports 12. These passages are closed against each other, and open alter- 12, 1919. Serial No. 337,418.

nately toward the opposite ends of the valve. In the valve on each side are annular channels 26 and 27. The respective service channels in the motor leading from the pump include annular channels 28, 29, at the respective ends of the valve overlying portions of the motor housing, the former of whlch communicates at 30 with a pump channel 31, and the latter with a pump channel 32.

Therefore, as the valve rotates, as through gears 33 from one of the crank shafts 17, the passages alternately communicate with the respective, pump channels to thereby receive and discharge the fluid from the pump for the operation of the motor. If the valve is divided into four sections, with pressure and discharge chambers varying alternately forone revolution of the valve, four piston strokes are necessary. That is the number of valve divisions are equal to the single strokes of the piston in one revolution, the valve divisions bein of course always in even number. F urthermore, the ratio of valve speed to crank pin speed is one half the number of valve divisions. For example, if the valve is driven from the crank shaft, a valve divided into four, six, eight, ten, .etc., sections, must be 'geared down to half, third, quarter, fifth,

etc., speed of the crank shaft.

With the valve arranged and operating as described, two opposite divisions are receiving fluid under pressure from the pump, while the remaining two divisions are receiving fluid from the cylinders, and therefore under'low pressure. It will therefore be apparent that the valve is balanced against the working fluid pressure.

The gear 19 when operating with an even number of cylinders is balanced, while with an odd number of cylinders a'slight, pressure will be established on the bearing. One half of each pinion is always in driving engagement with the gear 19, while the other half takes care of no-pressure stroke according to. the direction of drive. Evidently then'the pinion teeth have different tooth loads. For this reason I prefer to make the gear ratio even so that the same teeth will always bear the load. Thus the wear on the teeth is substantially uniform and will not seriously interfere with the operation of the device.

The principle of the balanced valve operation is clearly brought out in Figs. 4 a),

1l,though herethe motor is shown [with but five cylinders. The valve of the respective views show a varying number ofdivisions, with the valve speed correspondinl reduced, as before referred to. ving thus described the invention, what is claimed as new, is I 1. A hydraulic motor having a plurality of cylinders, a valve having two sets of fluid channels, and annular service channels at each end, the annular channels communicating alternately with alternate fluid channels of respective sets, one set of fluid channels delivering fiuidto a predetermined number of cylinders while the other set is receiving fluid from a corresponding number of cylinders. I

2. A hydraulic motorhaving a plurality of cylinders, a piston for each cylinder, a-

valve having two sets of fluid channels, and annular service channels at each end, the annular channels communicating alternamesses tively with alternate fluid channels of respeetive sets, one set of fluid channels'delivering fluid to a predetermined number of c linders while the other set is receiving fluid from a corresponding number of cylinders, and means for operating the valve at a speed having a ratio to the crank speed of one half of the valve channels.

3. A hydraulic motor having a lurality of cylinders, pistons therein, a va ve having anumber of fluid-passage divisions, one set of such divisions delivering fluid to a predetermined number of cylinders while a the other set is receiving fluid from a corresponding number of cylinders, means for controlling the number of piston strokes in each revolution of the motor in correspondence with the number of valve fluid-passage divisions, and means for operating the valve at a speed having a ratio to the crank speed of one half of the valve divisions.v

In testimony whereof I afiix my signature.

WDEMAR r. MAYER. 

